1. Field of the Invention
The present invention relates to a digital type electronic computer which is suitable to effect array processing of the type which makes it possible to execute array computations at a high speed (and which will be shortly referred to as an "array processor").
2. Description of the Prior Art
In scientific and technical computations, two-dimensional arrays, as are illustrated in the FORTRAN program of FIG. 1, are so demanded that they can be computed at a high speed. The one-dimensional and two-dimensional arrays will be shortly referred to as "vectors" and "arrays", respectively, in the following. In order to speed up the array computations, there have been taken until now the following two approaches. The first approach is the array processor system in which a number of processors are arranged two-dimensionally in parallel and execution occurs simultaneously in parallel for a number of array elements. This approach makes it possible to improve performance on principle in proportion to the number of the processors by increasing the processor number. In case the number of the array elements to be processed is smaller than that of the processors installed, however, the availability of the processor is so low that the approach does not economically pay. The second approach is the vector processor system in which the vector processings are speeded up by using vector registers and pipeline control computers. This system is represented by that which is disclosed in U.S. Pat. No. 4,128,880. The vector processor can speed up the processings of a single "Do" loop but has a limit to the speedup of its double loop processings. This is because the program of FIG. 1 is usually divided into single-loop processings A1 to AM, as shown in FIG. 2, which have to be serially executed.